Nordic: added the s110 scatter files

This commit adds the ability for a compile flag to be set from targets.py
which changes the soft device to s110.

The compile flag is: MCU_NRF51_16K_S110. In order to avoid duplication
of the startup file, for the 16K parts we introduce an S110 or S130
scatter file. This means all 16K platforms must define
MCU_NRF51_16K
and ONE of
MCU_NRF51_16K_S110 or MCU_NRF51_16K_S130

Based on an earlier commit by Mihail but modified to avoid copy/paste
of the startup code for S110/S130

Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>

libraries/mbed/targets/cmsis/TARGET_NORDIC/TARGET_MCU_NRF51822/TOOLCHAIN_ARM_STD/TARGET_MCU_NRF51_16K_S110/nRF51822.sct

@@ -0,0 +1,24 @@
+;WITHOUT SOFTDEVICE:
+;LR_IROM1 0x00000000 0x00040000  {
+;  ER_IROM1 0x00000000 0x00040000  {
+;   *.o (RESET, +First)
+;   *(InRoot$$Sections)
+;   .ANY (+RO)
+;  }
+;  RW_IRAM1 0x20000000 0x00004000  {
+;   .ANY (+RW +ZI)
+;  }
+;}
+;
+;WITH SOFTDEVICE:
+
+LR_IROM1 0x18000 0x0028000  {
+  ER_IROM1 0x18000 0x0028000  {
+   *.o (RESET, +First)
+   *(InRoot$$Sections)
+   .ANY (+RO)
+  }
+  RW_IRAM1 0x20002000 0x00002000  {
+   .ANY (+RW +ZI)
+  }
+}

libraries/mbed/targets/cmsis/TARGET_NORDIC/TARGET_MCU_NRF51822/TOOLCHAIN_GCC_ARM/TARGET_MCU_NRF51_16K_S110/NRF51822.ld

@@ -0,0 +1,151 @@
+/* Linker script to configure memory regions. */
+
+MEMORY
+{
+  FLASH (rx) : ORIGIN = 0x00016000, LENGTH = 0x2A000
+  RAM (rwx) :  ORIGIN = 0x20002000, LENGTH = 0x2000
+}
+
+OUTPUT_FORMAT ("elf32-littlearm", "elf32-bigarm", "elf32-littlearm")
+
+/* Linker script to place sections and symbol values. Should be used together
+ * with other linker script that defines memory regions FLASH and RAM.
+ * It references following symbols, which must be defined in code:
+ *   Reset_Handler : Entry of reset handler
+ *
+ * It defines following symbols, which code can use without definition:
+ *   __exidx_start
+ *   __exidx_end
+ *   __etext
+ *   __data_start__
+ *   __preinit_array_start
+ *   __preinit_array_end
+ *   __init_array_start
+ *   __init_array_end
+ *   __fini_array_start
+ *   __fini_array_end
+ *   __data_end__
+ *   __bss_start__
+ *   __bss_end__
+ *   __end__
+ *   end
+ *   __HeapLimit
+ *   __StackLimit
+ *   __StackTop
+ *   __stack
+ */
+ENTRY(Reset_Handler)
+
+SECTIONS
+{
+	.text :
+	{
+		KEEP(*(.Vectors))
+		*(.text*)
+
+		KEEP(*(.init))
+		KEEP(*(.fini))
+
+		/* .ctors */
+		*crtbegin.o(.ctors)
+		*crtbegin?.o(.ctors)
+		*(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors)
+		*(SORT(.ctors.*))
+		*(.ctors)
+
+		/* .dtors */
+ 		*crtbegin.o(.dtors)
+ 		*crtbegin?.o(.dtors)
+ 		*(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors)
+ 		*(SORT(.dtors.*))
+ 		*(.dtors)
+
+		*(.rodata*)
+
+		KEEP(*(.eh_frame*))
+	} > FLASH
+
+
+	.ARM.extab :
+	{
+		*(.ARM.extab* .gnu.linkonce.armextab.*)
+	} > FLASH
+
+	__exidx_start = .;
+	.ARM.exidx :
+	{
+		*(.ARM.exidx* .gnu.linkonce.armexidx.*)
+	} > FLASH
+	__exidx_end = .;
+
+	__etext = .;
+
+	.data : AT (__etext)
+	{
+		__data_start__ = .;
+		*(vtable)
+		*(.data*)
+
+		. = ALIGN(4);
+		/* preinit data */
+		PROVIDE_HIDDEN (__preinit_array_start = .);
+		KEEP(*(.preinit_array))
+		PROVIDE_HIDDEN (__preinit_array_end = .);
+
+		. = ALIGN(4);
+		/* init data */
+		PROVIDE_HIDDEN (__init_array_start = .);
+		KEEP(*(SORT(.init_array.*)))
+		KEEP(*(.init_array))
+		PROVIDE_HIDDEN (__init_array_end = .);
+
+
+		. = ALIGN(4);
+		/* finit data */
+		PROVIDE_HIDDEN (__fini_array_start = .);
+		KEEP(*(SORT(.fini_array.*)))
+		KEEP(*(.fini_array))
+		PROVIDE_HIDDEN (__fini_array_end = .);
+
+		*(.jcr)
+		. = ALIGN(4);
+		/* All data end */
+		__data_end__ = .;
+
+	} > RAM
+
+	.bss :
+	{
+		. = ALIGN(4);
+		__bss_start__ = .;
+		*(.bss*)
+		*(COMMON)
+		. = ALIGN(4);
+		__bss_end__ = .;
+	} > RAM
+
+	.heap (COPY):
+	{
+		__end__ = .;
+		end = __end__;
+		*(.heap*)
+		__HeapLimit = .;
+	} > RAM
+
+	/* .stack_dummy section doesn't contains any symbols. It is only
+	 * used for linker to calculate size of stack sections, and assign
+	 * values to stack symbols later */
+	.stack_dummy (COPY):
+	{
+		*(.stack*)
+	} > RAM
+
+	/* Set stack top to end of RAM, and stack limit move down by
+	 * size of stack_dummy section */
+	__StackTop = ORIGIN(RAM) + LENGTH(RAM);
+	__StackLimit = __StackTop - SIZEOF(.stack_dummy);
+	PROVIDE(__stack = __StackTop);
+
+	/* Check if data + heap + stack exceeds RAM limit */
+	ASSERT(__StackLimit >= __HeapLimit, "region RAM overflowed with stack")
+}

workspace_tools/targets.py

@@ -1017,30 +1017,77 @@ class MCU_NRF51(Target):
             binh.tofile(f, format='hex')
 
             
+# 16KB Nordic targets are tight on SRAM using S130 (default) so we
+# introduce two possible options:
+# 1) Use S130 (default) - for this derive from MCU_NRF51_16K
+# 2) Use S110  - for this derive from MCU_NRF51_16K_S110
+# Note that the 'default' option will track the default choice
+# for other Nordic targets, and so can take advantage of other
+# future SoftDevice improvements
+
+# The *_BASE targets should *not* be inherited from, as they do not
+# specify enough for building a target
+
 # 16KB MCU version, e.g. Nordic nRF51822, Seeed Arch BLE, etc.
-class MCU_NRF51_16K(MCU_NRF51):
+class MCU_NRF51_16K_BASE(MCU_NRF51):
     def __init__(self):
         MCU_NRF51.__init__(self)
         self.extra_labels += ['MCU_NORDIC_16K', 'MCU_NRF51_16K']
         self.macros += ['TARGET_MCU_NORDIC_16K', 'TARGET_MCU_NRF51_16K']
 
 # derivative class used to create softdevice+bootloader enabled images
-class MCU_NRF51_16K_BOOT(MCU_NRF51_16K):
+class MCU_NRF51_16K_BOOT_BASE(MCU_NRF51_16K_BASE):
     def __init__(self):
-        MCU_NRF51_16K.__init__(self)
+        MCU_NRF51_16K_BASE.__init__(self)
         self.extra_labels += ['MCU_NRF51_16K_BOOT']
         self.macros += ['TARGET_MCU_NRF51_16K_BOOT', 'TARGET_OTA_ENABLED']
         self.MERGE_SOFT_DEVICE = True
         self.MERGE_BOOTLOADER = True
 
 # derivative class used to create program only images for use with FOTA
-class MCU_NRF51_16K_OTA(MCU_NRF51_16K):
+class MCU_NRF51_16K_OTA_BASE(MCU_NRF51_16K_BASE):
     def __init__(self):
-        MCU_NRF51_16K.__init__(self)
+        MCU_NRF51_16K_BASE.__init__(self)
         self.extra_labels += ['MCU_NRF51_16K_OTA']
         self.macros += ['TARGET_MCU_NRF51_16K_OTA', 'TARGET_OTA_ENABLED']
         self.MERGE_SOFT_DEVICE = False
 
+class MCU_NRF51_16K(MCU_NRF51_16K_BASE):
+    def __init__(self):
+        MCU_NRF51_16K_BASE.__init__(self)
+        self.extra_labels += ['MCU_NRF51_16K_S130']
+        self.macros += ['TARGET_MCU_NRF51_16K_S130']
+
+class MCU_NRF51_16K_S110(MCU_NRF51_16K_BASE):
+    def __init__(self):
+        MCU_NRF51_16K_BASE.__init__(self)
+        self.extra_labels += ['MCU_NRF51_16K_S110']
+        self.macros += ['TARGET_MCU_NRF51_16K_S110']
+
+class MCU_NRF51_16K_BOOT(MCU_NRF51_16K_BOOT_BASE):
+    def __init__(self):
+        MCU_NRF51_16K_BOOT_BASE.__init__(self)
+        self.extra_labels += ['MCU_NRF51_16K_S130']
+        self.macros += ['TARGET_MCU_NRF51_16K_S130']
+
+class MCU_NRF51_16K_BOOT_S110(MCU_NRF51_16K_BOOT_BASE):
+    def __init__(self):
+        MCU_NRF51_16K_BOOT_BASE.__init__(self)
+        self.extra_labels += ['MCU_NRF51_16K_S110']
+        self.macros += ['TARGET_MCU_NRF51_16K_S110']
+
+class MCU_NRF51_16K_OTA(MCU_NRF51_16K_OTA_BASE):
+    def __init__(self):
+        MCU_NRF51_16K_OTA_BASE.__init__(self)
+        self.extra_labels += ['MCU_NRF51_16K_S130']
+        self.macros += ['TARGET_MCU_NRF51_16K_S130']
+
+class MCU_NRF51_16K_OTA_S110(MCU_NRF51_16K_OTA_BASE):
+    def __init__(self):
+        MCU_NRF51_16K_OTA_BASE.__init__(self)
+        self.extra_labels += ['MCU_NRF51_16K_S110']
+        self.macros += ['TARGET_MCU_NRF51_16K_S110']
+
 
 # 32KB MCU version, e.g. Nordic nRF51-DK, nRF51-Dongle, etc.
 class MCU_NRF51_32K(MCU_NRF51):
@@ -1247,9 +1294,9 @@ class NRF51_DONGLE_OTA(MCU_NRF51_32K_OTA):
         self.extra_labels = ['NRF51_DONGLE']
         self.macros += ['TARGET_NRF51_DONGLE']
 
-class NRF51_MICROBIT(MCU_NRF51_16K):
+class NRF51_MICROBIT(MCU_NRF51_16K_S110):
     def __init__(self):
-        MCU_NRF51_16K.__init__(self)
+        MCU_NRF51_16K_S110.__init__(self)
         self.EXPECTED_SOFTDEVICES_WITH_OFFSETS = [
             {
                 'name'   : 's110_nrf51822_8.0.0_softdevice.hex',
@@ -1264,15 +1311,15 @@ class NRF51_MICROBIT(MCU_NRF51_16K):
         ]
         self.macros += ['TARGET_NRF_LFCLK_RC']
 
-class NRF51_MICROBIT_BOOT(MCU_NRF51_16K_BOOT):
+class NRF51_MICROBIT_BOOT(MCU_NRF51_16K_BOOT_S110):
     def __init__(self):
-        MCU_NRF51_16K_BOOT.__init__(self)
+        MCU_NRF51_16K_BOOT_S110.__init__(self)
         self.extra_labels += ['NRF51_MICROBIT']
         self.macros += ['TARGET_NRF51_MICROBIT', 'TARGET_NRF_LFCLK_RC']
 
-class NRF51_MICROBIT_OTA(MCU_NRF51_16K_OTA):
+class NRF51_MICROBIT_OTA(MCU_NRF51_16K_OTA_S110):
     def __init__(self):
-        MCU_NRF51_16K_OTA.__init__(self)
+        MCU_NRF51_16K_OTA_S110.__init__(self)
         self.extra_labels += ['NRF51_MICROBIT']
         self.macros += ['TARGET_NRF51_MICROBIT', 'TARGET_NRF_LFCLK_RC']